Coelenterates

The only members of this group of interest here are the corals, which are a large group of invertebrates that live singly or in colonies. The hard corals construct elaborate, rigid calcareous exoskeletons, which can build up over generations, forming coral reefs. Soft corals are solitary, more flexible animals that have calcareous particles in their cell walls. 

Decorative coral is usually one of the hard corals. They are described by color, rather than by species, and live in tropical and temperate seas. The traditional orange or red precious coral is native to the Mediterranean and has been severely over-collected for hundreds of years. Most red coral on today s market is dyed coral from the Pacific Ocean. Black coral is a branching, tropical type that is also rare. There are a number of corals that are collected and sold today as black coral, but it is often merely dark-colored coral that has been dyed black. 

The artist who created this carving took advantage of the natural branched shape of the coral from which it is made. 

Cephalopods are the smartest and most complex of the mollusks. This group includes squid, octopus, cuttlefish, and chambered nautilus. The ammonites were an extremely diverse and successful group of cephalopods that roamed the world s oceans for millions of years until their extinction at the end of the Cretaceous period, about 65 million years ago. 

Reproduction was inhibited among the most sensitive species of aquatic animals at water concentrations of 0.03-1.6 xg Hg/L. For less sensitive marine invertebrates such as hydroids, protozoans, and mysid shrimp, reproduction was inhibited at concentrations between 1.1 and 2.5 xg Hg +/L this range was 5.0-71.0 xg/L for more resistant species of marine invertebrates. 

In the planarian Dugesia dorotocephala, asexual fission was suppressed at 0.03-0.1 xg organomercury/L at 80.0-100.0 xg methyl-mercury/L, behavior was modified and regeneration retarded. 

Rapid accumulation of mercury compounds, especially organomercury compounds, by 

Persistence of mercury in moUuscan tissues is about intermediate between that of fish and cmstaceans. Time to eliminate 50% of biologically assimilated mercury and its compounds (Tbl/2) ranged from 20 to 1200 days 

In mysid shrimp (Mysidopsis bahia), a sensitive species, the abortion rate increased and 

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Goelenterate. Coelenterates Penilla reformis (sea pansy) -cradViequoreaforskalea (jelly fish) produce bioluminescence by similar processes (223). The basic luciferin stmcture is (49) (224) and excited amide (50) is the emitter. The stmctural relationship to Varela is evident. A stmctural analogue where R = CH is active ia bioluminescence. The quantum yield is about 4% (223), with at 509 nm (56). This reaction iavolves a charge transfer between green fluorescent proteia and the excited-state coelenterate oxylucifetin. 

Organisms in the phylum Ctenophora, commonly known as comb jellies, are included at the end of this chapter because of their close relationship to coelenterates. 

Other hydrozoans. Various bioluminescent coelenterates have been comparatively studied in reference to the components necessary for their in vivo luminescence (Morin and Hastings, 1971a Cormier et al., 1973 Shimomura and Johnson, 1975b, 1979b). 

The name of coelenterazine. We suggested calling the new luciferin coelenterazine (Shimomura and Johnson, 1975b), although Inoue et al. (1976) named it Watasenia preluciferin. The compound has been called by various other names, such as coelenterate luciferin, coelenterate-type luciferin, Oplopborus luciferin, and Renilla luciferin. However, these two-word chemical names are cumbersome to use and inconvenient when applying a chemical prefix or suffix. Currently, the name coelenterazine is widely and commonly used. 

Cormier, M. J., et al. (1973). Evidence for similar biochemical requirements for bioluminescence among the coelenterates. 1. Cell. Physiol. 81 291-298. 

Hart, R. C., Stempel, K. E., Boyer, P. D., and Cormier, M. J. (1978). Mechanism of the enzyme-catalyzed bioluminescent oxidation of coelenterate-type luciferin. Biochem. Biophys. Res. Commun. 81 980-986. 

Harvey, E. N. (1921). Studies on bioluminescence. XIII. Luminescence in the coelenterates. Biol. Bull. 41 280-287. 

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